This invention relates to apparatus for electrodepositing a metallic layer having a particular thickness. More particularly, the invention relates to electrodeposition on an article in a metal-salt solution by means of a sacrificial anode which is connected to a DC voltage source, a current transformer for measuring the anode current, and a switching device for disconnecting the DC voltage source.
Such apparatus is used particularly for correcting etched or engraved printing cylinders for gravure printing where it is necessary for brightening the printed picture, by applying a layer of a given thickness in depressions of the printing cylinder in a limited correction area. The thickness of the layer applied depends on the magnitude of the anode current, the size of the anode, a material-dependent deposition equivalent, a shape-dependent current yield factor, the ratio of the size of the anode to the area of the correction region, and on the length of time. After the desired layer thickness is reached, the deposition process is to be terminated automatically.
There is need for an apparatus of the type mentioned above for use with a high degree of automation and having maximum flexibility in putting in the technological parameters.